What is a normal transferrin saturation level?

A normal transferrin saturation (TSAT) level is generally 20–50%. Values below 20% may indicate iron depletion, while values below 10% are consistent with significant iron deficiency. Values above 50% may suggest iron overload, and values above 75% are strongly associated with hemochromatosis or significant iron excess.

How is transferrin saturation calculated?

Transferrin saturation is calculated by dividing serum iron by Total Iron-Binding Capacity (TIBC), then multiplying by 100 to express it as a percentage: TSAT (%) = (Serum Iron / TIBC) × 100. Both values must be in the same units (either µg/dL or µmol/L) for an accurate result.

What does low transferrin saturation mean?

A low TSAT (below 20%) indicates that less iron is bound to transferrin than normal, which can mean iron stores are depleted. This is commonly seen in iron-deficiency anemia, chronic blood loss, inadequate dietary iron absorption, or functional iron deficiency in chronic kidney disease. A TSAT below 10% is typically considered indicative of significant iron deficiency.

What does high transferrin saturation mean?

An elevated TSAT (above 50%) suggests that more iron is circulating than the transferrin can adequately handle. This can occur in hereditary hemochromatosis, liver disease, hemolytic anemia, excessive iron supplementation, or repeated blood transfusions. A TSAT consistently above 45–50% warrants further investigation, including serum ferritin and genetic testing for HFE mutations.

What is the difference between transferrin saturation and ferritin?

Transferrin saturation (TSAT) measures the percentage of transferrin that is currently carrying iron — it reflects the current supply of iron available for use. Serum ferritin, on the other hand, reflects iron stores in the body's tissues. Both markers are used together to diagnose iron status: low TSAT with low ferritin suggests absolute iron deficiency, while low TSAT with normal or high ferritin may suggest functional iron deficiency (as seen in chronic disease or inflammation).

Last updated December 7, 2025

Transferrin Saturation Calculator

Also known as:TSAT CalculatorIron Saturation CalculatorSerum Iron to TIBC RatioIron Binding Saturation Calculator

Medically Reviewed

Dr. Prem Pais, MD, DM

Iron Metabolism & Hematology Researcher, St. John's Medical College India

Hematology

Reviewed September 16, 2025

NIH — Iron Deficiency Anemia

Disclaimer

This calculator provides transferrin saturation estimates for informational purposes only and does not constitute a medical diagnosis. TSAT must be interpreted alongside serum ferritin, complete blood count, clinical history, and other laboratory values. Results may be affected by inflammation, liver disease, pregnancy, and recent iron supplementation. Always consult a qualified physician or hematologist for proper interpretation and medical advice.

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Frequently Asked Questions

Everything you need to know about transferrin saturation and iron status

Transferrin Saturation Calculator

Calculate TSAT from serum iron and TIBC

Unit System

Serum Iron

µg/dL

Normal range: 60–170 µg/dL (adults)

Total Iron-Binding Capacity (TIBC)

µg/dL

Normal range: 240–450 µg/dL (adults)